1. Field of the Invention
This invention relates in general to vehicle load supporting structures and in particular to vehicle axles and frame components formed of two or more pieces of sheet metal.
2. Description of the Prior Art
In recent years, there has been an increased demand from both the state and federal governments and the comsuming public for utility vehicles such as the light truck and van which achieve better gas mileage and increased payload. One area of concern is the axle which must be strong yet is an especially important area for weight savings since it represents unsprung weight. An early technique for weight savings was the replacement of the forged axle with a one piece pressed axle beam having a flanged, channel-shaped cross-section and upwardly formed end portions. This axle beam opens upwardly with the end portions being closed and reinforced by a contoured plate welded to the opposed beam flanges which serves as a spring seat and having knuckle pieces welded thereto for attachment to the vehicle wheels. Such a axle is shown in U.S. Pat. No. 3,072,441.
Still another attempt in producing a lighter weight sheet metal axle is illustrated and described in U.S. Pat. No. 2,218,217 wherein metal torque resisting parts are disposed to extend crosswise within the interior of the hollow beam member to resist shearing forces and bending strains.
U.S. Pat. No. 1,931,105 relates to a hollow vehicle axle arrangement formed of stamped metal members welded together to form a substantially integral structure of cross-section to withstand the stresses and strains imposed on critical portions of the axle.
The axle structure shown in U.S. Pat. No. 1,841,735 comprises a one piece tubular axle having the end portions thereof shaped and welded together to provide transversely extending cylindrical members with inturned annular flanges partially closing each end.
Another vehicle axle structure is illustrated in U.S. Pat. No. 1,219,153 wherein the axle body is formed of two parts generally C-shaped in cross-section having internally disposed reinforcing members welded thereto.